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2015 Kia Optima

Owner reports · Recalls · Investigations

More warning signs than most Optima years

Owner complaints for the 2015 Kia Optima are substantially higher than the model-year median of 186.5.

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When problems were reported

Mileage at the reported incident

493 reports with mileage · 514 unknown

NHTSA’s mileage field refers to the reported incident, not necessarily the filing date. This shows report counts, not the likelihood of a failure.

What to inspect

Issues worth paying extra attention to based on owner reports.

  • Engine. Review the 621 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Electrical System. Review the 135 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Structure. Review the 76 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →

NHTSA owner reports · September 18, 2026 snapshot.

31 crash reports74 fire reports20 injury reports

Fuel/propulsion System complaints

46 reports
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Mileage unknown · Dec 11, 2023
EngineFuel/propulsion System

My car has been consuming lots of oil. I took it in for an oil change and while test driving two of the mechanics stated the oil light came on and it ran out of oil on the test drive. Instead of saying anything about a possible issue with the engine, they went ahead and put oil in it and sent me on my way. Since, my car is stil…

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My car has been consuming lots of oil. I took it in for an oil change and while test driving two of the mechanics stated the oil light came on and it ran out of oil on the test drive. Instead of saying anything about a possible issue with the engine, they went ahead and put oil in it and sent me on my way. Since, my car is still consuming loads of oil. I've taken it into the dealership several times for the same issue and each time they told me they can't do anything about it until it runs out of oil. One person advised to not put oil in it. Now the engine light came on, so I took it in again and this time I was told the cylinders have gone bad and one person that worked there said to let it run out of oil, but you didn't hear that from me, and they will replace the engine for free. I said, so I'm supposed to let the car die while I'm driving it, what happens if the car quits running in the middle of a turn and I get hit, the guy looked at me and said nothing. In addition, he asked if I had an extended warranty as its covered under an extended warranty. I'm pretty sure I did buy one, but I couldn't remember, so I called up the dealership I purchased it from and they said they couldn't tell me either since, they don't keep any paperwork after 7 years, and its been 8 years.They also said it wouldn't matter as it wouldn't be covered because of mileage. I have been complaining about the oil way before my mileage was over and I'm pretty sure I read something about mileage ext on Kia for this same issue.The last time I drove it, I was sitting idle in my car and the oil light came on, so I called the dealership, they asked if it started back up and I wasn't sure, so I tried and it started back up and the oil light went back off again, so I didn't have it towed down there. Now my understanding there is a new recall on the car with the fuel and it could catch fire and was stated to park it, so its been sitting for three months with nothing fixed.The car needs a new engine.

NHTSA ODI #11559552

Mileage unknown · Nov 7, 2023
EngineFuel/propulsion System

Engine failure & fuel leak. Also oil was burning extremely fast . I had taking it to the dealership while back ago for a recall and said it was fixed. Few months later gas started running out fast. A check light engine came on saying there was an evaporation leak. I did call the dealership to see what exactly they fixed, email…

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Engine failure & fuel leak. Also oil was burning extremely fast . I had taking it to the dealership while back ago for a recall and said it was fixed. Few months later gas started running out fast. A check light engine came on saying there was an evaporation leak. I did call the dealership to see what exactly they fixed, emailed them. They kept telling me they would call me back and never did. Wouldn’t get any emails back. I took it upon headquarters to let them know about the oil burning fast and emailed. And called them. Apparently there was nothing they can do and told me I have to call the dealership. I took the car to my mechanic because I trust him more than the actual dealership at this point. And I brought up concerns about my safety being in that car. No one heard me out or seemed to care. And now forward months later after check light engines on and the pcv valve getting changed, purge valve. The light stopped coming on after changing the purge valve got change which linked to the code that showed up. I started seeing online that Kia optima’s have so many engine problems , misfires etc. and now my Kia has an engine failure. I tried to contact Kia again by entering the info for a settlement and I was told there is nothing they can do about it. So now I’m left with $5,500 to finish paying off my loan for the car and can’t even drive the car anymore. I havnt felt safe In my car for months and no one would hear me out.

NHTSA ODI #11554030

Mileage unknown · Oct 28, 2023
Electrical SystemEngineFuel/propulsion SystemFire

Engine lost power and when restart was attempted, it could torn turn over. Tried restarting 3 times with no success. After this, smoke started coming from the hood. I opened the hood and noticed a small flame at the driver side bottom of the engine compartment. Flame intensified and grew and eventually I extinguished with a fire…

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Engine lost power and when restart was attempted, it could torn turn over. Tried restarting 3 times with no success. After this, smoke started coming from the hood. I opened the hood and noticed a small flame at the driver side bottom of the engine compartment. Flame intensified and grew and eventually I extinguished with a fire extinguisher. I had just replaced the starter that same week and replaced some wiring at a local car repair facility.

NHTSA ODI #11552409

Mileage unknown · Oct 8, 2023
EngineFuel/propulsion SystemVehicle Speed Control

1st problem happened when I was at a complete stop, at a traffic light, in rush hour traffic. All the sudden steam started coming out from underneath my hood. I instantly looked at my temperature gauge and it did not show anything however I knew something was wrong when the light turned green I immediately pulled over, out of th…

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1st problem happened when I was at a complete stop, at a traffic light, in rush hour traffic. All the sudden steam started coming out from underneath my hood. I instantly looked at my temperature gauge and it did not show anything however I knew something was wrong when the light turned green I immediately pulled over, out of the street as far as I can get without being hit by other cars. I put on my hazard lights. Pop the hood. I had a gallon jug in my trunk. And I walked to a store to fill it up with water. Came back, poured the entire gallon into the radiator. Waited for at least 30 minutes. Started the car and made it home. After that incident, the problems with this 2015 Kia Optima has snowballed. It just amazes me that it has started happening 2000 miles after my extended warranty expired. I had to purchase and replace spark plugs, the coil packs, two other sensor things, which I do have the receipts for and now the car reeks a gasoline and it automatically kicks into overdrive and I lose my reading on my tachometer, this puts it into a disabled mode, I'm on the freeway in Russia traffic, trying to pull over without getting into an accident. Do I believe this is a safety concern? You're damn right I do am I mad yes. I am taking my k i a into the dealership. After doing my research on this make and model, is the dealership doesn't honor what the claims department and the media response to this problem. Will then I will leave the car with Kia because I cannot afford a new engine. I will have to call to finance company and let them know that I voluntary I'm letting them come repo this car, good luck selling it

NHTSA ODI #11548919

Mileage unknown · Sep 20, 2023
EngineFuel/propulsion SystemVehicle Speed Control

Excessive shaking of engine, stalled out while driving on highway, knocking in the engine.

NHTSA ODI #11545569

115,696 miles · Sep 7, 2023
EngineFuel/propulsion SystemPower TrainCrash

I HAVE 2015 KIA OPTIMA GREY OR PLATINUM GRAPHITE EXTERIOR COLOR SINCE AUG 2019 I HAD AN TBONE ACCIDENT LAST DEC 26 2021 WHICH IAM NOT AT FAULT FOR NEVER RECEIVED ANY TYPE OF COMFORT CARE CLAIM IT WAS DURING COVID PANDEMIC I WAS IN THE PROCESS OF GRIEVIANCE BEING HATE LEFT IN DESPAIR ALSO JOB LOSS WITH NO INCOME UNSTABLE LIVING S…

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I HAVE 2015 KIA OPTIMA GREY OR PLATINUM GRAPHITE EXTERIOR COLOR SINCE AUG 2019 I HAD AN TBONE ACCIDENT LAST DEC 26 2021 WHICH IAM NOT AT FAULT FOR NEVER RECEIVED ANY TYPE OF COMFORT CARE CLAIM IT WAS DURING COVID PANDEMIC I WAS IN THE PROCESS OF GRIEVIANCE BEING HATE LEFT IN DESPAIR ALSO JOB LOSS WITH NO INCOME UNSTABLE LIVING SITUATION WHICH I WAS LIVING ON MY PERSONAL VEHICLE BEEN GOING THROUGH FINANCIAL HARDSHIP UNTIL PRESENT I HAVENT BEEN DRIVEN UNTIL I BROUGHT TO KIA DEALERSHIP JAN 1ST OF 2023 DUE TO MY PERSONAL INJURY AND CAR ACCIDENT IT WAS LEFT PARKED GOT TOWED WITH BUSTED WINDOWS HAD MY PERSONAL BELONGINGS BEING GONE MISSING.... I HAVE ROUGH YEARS... IT WAS DIFFICULT FOR ME TO GET BACK UP IN MY FEET MY CAR HAS RECALLS ARENT BEING REPAIRED FAIRLY. THIS WILL BE MY FIRST TIME TO ADHERE MY CONCERNS I WOULD LIKE TO GET SOME ASSISTANCE IF POSSIBLE...I THANK YOU IN ADVANCE

NHTSA ODI #11543067

Mileage unknown · Aug 30, 2023
Electrical SystemEngineFuel/propulsion SystemFire

I WAS DRIVING NORTH ON THE 57 FREEWAY AND MY CAR STOP RUNNING AND I PULLED ON THE SIDE OF THE FREEWAY AND MY CAR CATCH ON FIRE. EVERYTHING STARTED IN THE ENGINE. I CALLED KIA AND MADE A COMPLAINT AND THEY TOLD ME IT WAS NOT UNDER WARRANTY AND THEY COULD NOT HELP ME.

NHTSA ODI #11541660

Mileage unknown · Jul 20, 2023
Electrical SystemEngineFuel/propulsion System

I driving my vehicle is just started powering down and didn’t want to turn on again. We jumped started it thinking it was the battery but it checked out fine. The vehicle doesn’t want to start anymore and the mobile mechanic said the engine had ti be replaced since it was off the timing loop. No engine or vehicle lights were in …

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I driving my vehicle is just started powering down and didn’t want to turn on again. We jumped started it thinking it was the battery but it checked out fine. The vehicle doesn’t want to start anymore and the mobile mechanic said the engine had ti be replaced since it was off the timing loop. No engine or vehicle lights were in and no prior issues were appearing.

NHTSA ODI #11533417

Mileage unknown · Apr 28, 2023
Fuel/propulsion SystemUnknown Or Other

My 2015 Kia is burning 1. a lot of oil and 2. The second is the car smells of gas scared it is one that will catch fire

NHTSA ODI #11519490

Mileage unknown · Mar 13, 2023
Fuel/propulsion SystemUnknown Or Other

The fuel rail seals keep leaking and spraying fuel all over . Fuel rail needs replaced

NHTSA ODI #11511637

Official recalls

4

23V652000 · Service Brakes, Hydraulic:antilock/traction Control/electronic Limited Slip:control Unit/module

Sep 25, 2023

Kia America, Inc. (Kia) is recalling certain 2010-2019 Borrego, 2014-2016 Cadenza, 2010-2013 Forte, Forte Koup, Sportage, 2015-2018 K900, 2011-2015 Optima, 2011-2013 Optima Hybrid, Soul, 2012-2017 Rio, 2011-2014 Sorento, and 2010-2011 Rondo vehicles. The Hydraulic Electronic Control Unit (HECU) may experience an electrical short, which can result in an engine compartment fire while parked or driving.

Consequence & remedy

Consequence: An engine compartment fire while parked or driving can increase the risk of injury.

Remedy: Owners are advised to park outside and away from structures until the recall repair is complete. Dealers will replace the HECU fuse, free of charge. Interim notification letters, notifying owners of the safety risk, were mailed November 14, 2023. Owner notification letters were mailed March 29, 2024 through June 18, 2024. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC284.

21V331000 · Service Brakes, Hydraulic:antilock/traction Control/electronic Limited Slip:control Unit/module

May 10, 2021

Kia Motors America (Kia) is recalling certain 2013-2015 Optima and 2014-2015 Sorento vehicles previously recalled under recall 20V-519. Brake fluid may leak inside the Hydraulic Electronic Control Unit (HECU), possibly resulting in an electrical short.

Consequence & remedy

Consequence: An electrical short in the HECU increases the risk of a fire while parked or driving.

Remedy: Owners are advised to park outside and away from other vehicles and structures until the recall repair is completed. Dealers will install a new multi-fuse, and inspect the HECU for leaks, replacing the HECU if necessary, free of charge. Owner notification letters were mailed on July 2, 2021. This recall supersedes previous NHTSA recall number 20V-519. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC212.

20V519000 · Service Brakes, Hydraulic:antilock/traction Control/electronic Limited Slip:control Unit/module

Aug 27, 2020

Kia Motors America (Kia) is recalling certain 2013-2015 Optima and 2014-2015 Sorento vehicles. Brake fluid may leak inside the Hydraulic Electronic Control Unit (HECU), possibly resulting in an electrical short.

Consequence & remedy

Consequence: If the HECU short circuits, there is an increased risk of an engine compartment fire.

Remedy: Kia will notify owners, and dealers will inspect the HECU for leaking brake fluid and replace the HECU if necessary, free of charge. Owners are advised to park outside and away from other vehicles and structures until the recall repair is completed. The recall began October 20, 2020. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC197.

18V907000 · Engine; Fuel System, Gasoline:delivery:hoses, Lines/piping, And Fittings

Dec 19, 2018

Kia Motors America (Kia) is recalling certain 2011-2017 Optima, 2012-2017 Sorento and 2011-2018 Sportage vehicles that previously received an engine replacement under recall number 17V-224, warranty, or the Knock Sensor Detection System (KSDS) Product Improvement Campaign. The high pressure fuel pipe that connects to the fuel pump outlet may have been damaged, misaligned or improperly torqued during the engine replacement procedure, possibly causing a fuel leak.

Consequence & remedy

Consequence: A fuel leak in the presence of an ignition source can increase the risk of a fire.

Remedy: Kia has notified owners, and dealers will inspect and replace the fuel pipe, as necessary, free of charge. The recall began January 17, 2019. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC172.

Additional source detail variants (2)

Engine

Kia Motors America (Kia) is recalling certain 2011-2017 Optima, 2012-2017 Sorento and 2011-2018 Sportage vehicles that previously received an engine replacement under recall number 17V-224, warranty, or the Knock Sensor Detection System (KSDS) Product Improvement Campaign. The high pressure fuel pipe that connects to the fuel pump outlet may have been damaged, misaligned or improperly torqued during the engine replacement procedure, possibly causing a fuel leak.

Consequence: A fuel leak in the presence of an ignition source can increase the risk of a fire.

Remedy: Kia has notified owners, and dealers will inspect and replace the fuel pipe, as necessary, free of charge. The recall began January 17, 2019. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC172.

Fuel System, Gasoline:delivery:hoses, Lines/piping, And Fittings

Kia Motors America (Kia) is recalling certain 2011-2017 Optima, 2012-2017 Sorento and 2011-2018 Sportage vehicles that previously received an engine replacement under recall number 17V-224, warranty, or the Knock Sensor Detection System (KSDS) Product Improvement Campaign. The high pressure fuel pipe that connects to the fuel pump outlet may have been damaged, misaligned or improperly torqued during the engine replacement procedure, possibly causing a fuel leak.

Consequence: A fuel leak in the presence of an ignition source can increase the risk of a fire.

Remedy: Kia has notified owners, and dealers will inspect and replace the fuel pipe, as necessary, free of charge. The recall began January 17, 2019. Owners may contact Kia customer service at 1-800-333-4542. Kia's number for this recall is SC172.

Model-level recall history does not show whether a particular VIN is affected or has received a repair. Check a VIN with NHTSA ↗

NHTSA investigations

4

AQ23002 · Hyundai And Kia Abs Module Fires

Opened Nov 17, 2023 · No close date supplied

Status: open (inferred from source dates) · Service Brakes, Hydraulic:antilock/traction Control/electronic Limited Slip:control Unit/module

The Office of Defects Investigation (ODI) has received eight Hyundai Motor America (Hyundai) and eight Kia America, Inc. (Kia) Part 573 Recall Reports between 2016 and 2023. The combined 16 safety recalls all involve the antilock braking system (ABS) modules or Hydraulic Electronic Control Units (HECU) manufactured by the equipment supplier Mando. The Part 573 Recall Reports contain varying defect descriptions and differing remedy descriptions for the same or similar equipment supplied by Mando. Safety recalls included in this Audit Query (AQ) review include: Hyundai recalls 20V-520, 20V-543, 21V-161, 21V-160, 21V-303, 22V-056, 22V-810, and 23V-651. Kia recalls 16V-815, 20V-518, 20V-519, 21V-137, 21V-331, 22V-051, 22V-800, and 23V-652 The purpose of this AQ is to evaluate the timeliness and scoping of Hyundai and Kia’s defect decision making and adherence with reporting requirements; and understand the varying defect descriptions and remedies between these recalls.

DP22003 · Loss Of Motive Power

Opened Sep 12, 2022 · Closed Dec 12, 2023

Status: closed (inferred from source dates) · Engine

The National Highway Traffic Safety Administration (NHTSA) received a letter dated July 13, 2022, petitioning the Agency to initiate a safety defect investigation into loss of motive power allegations attributed to oil drain pan assembly failures on certain Hyundai Motor America, Inc. and Kia America, Inc. vehicles spanning Model Years (MY) 2005-2021. The Petitioners cited examples of complaints indicating that the subject vehicles were experiencing rapid loss of engine oil due to oil drain plug back outs, resulting in loss of motive power and/or catastrophic engine damage. Additional complaints were provided which alleged that the oil drain pans lack sufficient structural integrity and are susceptible to cracking. The petition itself can be reviewed at NHTSA.gov under ODI number 11481745. On September 12, 2022, the Office of Defects Investigation (ODI) opened Defect Petition (DP22-003) to evaluate the Petitioners’ request. The Petitioners have provided additional complaints within four supplemental letters dated January 31, 2023, March 21, 2023, May 23, 2023, and August 4, 2023. ODI’s evaluation included the review and analysis of the complaints and supporting information submitted by the Petitioners, as well as additional complaints submitted directly to NHTSA which referenced either the oil drain plug or a crack in the oil pan. After reviewing the available data, ODI has not identified evidence that would support opening a defect investigation into the oil drain pan assemblies of the subject vehicles. Based on a review of the available information, a loss of motive power resulting from an oil drain plug back out has not occurred between the initial sale of a vehicle and the completion of its first oil change. If during an oil change service, a technician fails to remove the existing drain plug gasket before installing a new gasket, it is likely that a proper seal between the drain plug and the oil pan will not be made. An improper seal between the drain plug and oil pan could lead to the backing out on the drain plug, resulting in the sudden loss of oil while driving. Additionally, the provided examples of oil pan cracks were localized to the immediate vicinity of the oil drain plug and/or appeared to be the result of direct-contact with a tool during servicing.  There is no information to support that a vehicle-based defect exists relating to the oil pan assembly, and instead the documented incidents are related to the failure to follow the proper maintenance procedures during oil change service. In October 2023, Hyundai published a Technical Service Bulletin (TSB) that provided detailed instructions for oil change service on its gasoline powered vehicles, specifically highlighting the need to remove and replace the existing drain plug gasket prior to reinstalling the drain plug. After a thorough review of the material submitted by the petitioner, the information already in NHTSA's possession, and the potential risks to motor vehicle safety implicated by the petitioners' allegations, NHTSA does not believe that a formal investigation is warranted. Therefore, the petition is denied. A Federal Register Notice (FRN) further detailing NHTSA’s reasons for denial of the petition will be published. The reference numbers for the complaints to NHTSA cited by the petitioner can be found in the petition submission documents in the public file for DP22-003. To review those complaints and the additional complaints ODI added to its evaluation which are cited in the Closing Resume ODI Report Identification Number document, go to NHTSA.gov.

DP21003 · Throttle Control System Vulnerabilities

Opened Nov 12, 2021 · Closed Jun 20, 2023

Status: closed (inferred from source dates) · Vehicle Speed Control:throttle

The Office of Defects Investigation (ODI) of the National Highway Traffic Safety Administration (NHTSA) received a petition letter dated October 10, 2021, requesting an investigation of possible defects in the electronic throttle control (ETC) system on certain Kia vehicles resulting in the opening of DP21-003. Accordingly, Model Year (MY) 2005-2016 Kia Optima/K5, MY 2006-2015 Kia Sorento, MY 2007-2016 Hyundai Elantra, MY 2007-2016 Hyundai Santa Fe, MY 2006-2015 Hyundai Sonatas are all part of the subject population. The petition was originally filed as a Vehicle Owner Questionnaire that can be reviewed at NHTSA.gov under reference (ODI) number 11439675.On November 12, 2021, ODI opened Defect Petition DP21-003 to evaluate the petitioner?s request. ODI performed trend analyses of the VOQs related to vehicle speed control issues for all the subject vehicles and found that none of the 52 Model/Model Year Hyundai/Kia vehicles demonstrated any actionable trend that warranted an investigation.Petitioners submitted 1119 VOQs and non-VOQ cases in which sudden uncommanded acceleration (SUA) or loss of motive power (LOMP) incidents were alleged.For the 1119 reports, 220 were incidents involving crashes, from which 69 subject Hyundai-Kia vehicles were inspected by Hyundai/Kia dealer technicians, Hyundai/Kia engineers, and/or third-party representatives.ODI found the inspections identified no vehicle defects related to the ETC system.Of the 220 crash-involved reports, 13 Event Data Recorder (EDR) records were downloaded successfully and 11 of those indicated driver error: (i.e.) pedal misapplication.A condition where the accelerator pedal is mistakenly applied instead of the brake pedal when the driver wants to stop the vehicle.In addition, ODI reviewed a scientific journal paper published in Forensic Science International in 2016 by Mr. Park et al ., as well as related test videos. ODI does not believe there is any evidence of uncontrollable SUA occurrences in any of the tests reviewed. NHTSA's Office of Vehicle Safety Compliance (OVSC) reviewed the allegations regarding the potential noncompliance with Federal Motor Vehicle Safety Standard No. 124.Based on the information provided, the Agency concludes there is insufficient information for us to determine if a possible non-compliance exists.Finally, both Hyundai and Kia informed ODI that all their vehicles manufactured after 2012 were equipped with an ETC management system, in which the engine speed will go to idle when the system sees signals from both the brake pedal and accelerator pedal at the same time; this is commonly known as the brake-throttle override system.After thoroughly assessing the material submitted by the petitioner, information already in NHTSA's possession, information submitted by Hyundai and Kia in response to an Information Request letter, and the potential risks to safety implicated by the petitioner's allegation, NHTSA does not believe that a formal investigation is warranted. After full consideration of appropriate factors, the petition is denied. A Federal Register Notice (FRN) further detailing NHTSA?s reasons for denial of the petition will be published.

EA19001 · Electrical Overstress

Opened Apr 19, 2019 · Closed Sep 19, 2024

Status: closed (inferred from source dates) · Air Bags: Air Bag/restraint Control Module

The Office of Defects Investigation (ODI) opened this investigation to determine if the failure of airbags to deploy during severe crashes, in certain vehicles, was the result of a safety related defect.  During the investigation a complex failure was studied that can result in non-deployment of subject vehicle air bags and other restraint system devices in severe crash events. The subject vehicles may be equipped with an airbag control unit (ACU) for the supplemental restraint system (SRS) Electronic Control Unit (ECU) manufactured by ZF-TRW.  The ECU receives signals from crash sensors mounted in the vehicle and deploys the vehicle air bags and seat belt pretensioners in accordance with manufacturer design specifications.  The ECU in the subject vehicles contains a model DS84 application-specific integrated circuit (ASIC) which controls the communication of the crash sensor signal, firing commands (i.e., when to deploy the airbag(s) and/or pretensioners), and fault information (e.g., diagnostic trouble codes). In September 2016, FCA announced recall 16V-668 for certain model year (MY) 2010 to 2014 Chrysler, Dodge and Jeep products manufactured with the subject ZF-TRW ACU.  In this recall, FCA discussed an EOS condition that resulted in a failure of the subject DS84 ASIC, which caused air bag non-deployment.  FCA noted that the defect condition had only been observed in vehicles equipped with sensor harnessing routed across the front of the vehicle.  Other FCA vehicles that also used the subject ACU, but were not equipped with cross-car harnessing, had not experienced EOS failures, despite similar time in service. During the course of this investigation, ODI sent two separate Information Request (IR) letters to six vehicle manufactures (including FCA, Hyundai, Honda, Kia, Mitsubishi, and Toyota) and one IR letter to ZF-TRW.  These IR letters resulted in ODI receiving comprehensive data from these manufacturers and suppliers. Studies of this data found that the DS84 ASIC does not have sufficient protection against negative electrical transients or electrical overstress (“EOS”) that can be generated in certain severe crashes.  An electrical transient occurs when the electrical power supplied to a circuit changes momentarily over a short duration of time.   In these severe crash cases, the crash sensors and other powered wiring can be damaged and short circuited so as to create a negative electrical transient of sufficient intensity and duration (that are outside the vehicle manufacturer's specification) to damage the ASIC before the restraint device deployment signal is received by the SRS ECU.  This damaged signal can lead to incomplete or nondeployment of the air bags and/or pretensioners.  Airbag non-deployment and/or lack of pretensioner operation can increase the risk or severity of injury in a crash.A total of 8 fatalities and 14 injuries were associated with known EOS events. The common element in all investigated manufacturers vehicles is the SRS ECU containing a DS84 ASIC manufactured by ZF-TRW.  The risk associated with the ASIC is equally shared among all OEMS involved in the investigation.  The actual real-world risk can be mitigated by other factors which were assessed by ODI during this investigation. The first mitigating factor involves protections built into the ACU design which protect the DS84 ASIC from damage.  There are multiple strategies and levels of protection employed by different OEMs that provide effective EOS mitigation.  The two most common strategies at the ACU level are circuit protection diodes on the remote senor signal lines, and current limiting resistors that protect critical components. The second mitigating factor is found at the vehicle level and involves the location and routing of the wires leading from the crash sensors to the SRS ECU.  If the wires are well protected in a crash and are not routed with other power wires carrying large currents, the risk for an EOS event is significantly reduced or eliminated. These design specific factors combine to produce a spectrum of risk for the vehicles equipped with ACUs using the DS84 ASIC.  Given the many of years of field exposure, it is possible to divide the subject population into two groups; vehicles which have experienced EOS events, and vehicles which have not experienced EOS field events. Four of the six OEMs involved in this investigation have experienced EOS field events on at least one of their models equipped with a DS84 ASIC.  All vehicle models (including the Toyota models identified in the Failure Report Summary of the opening resume for this investigation) with field events have been recalled.  In an abundance of caution, ODI kept this investigation open five years to monitor field performance and did not identify any field events on vehicles not included in existing safety recalls. Given the spectrum of risk identified in this investigation and that all vehicles with a demonstrated unreasonable risk have been recalled, ODI is closing this investigation. ODI is closing this investigation with the following manufacturer safety recalls: 16V-668, 18E-043, 18V-137, 18V-363, and 20V-024.  With the recall actions taken by the subject vehicle and equipment manufacturers, this investigation is closed. The closing of this investigation does not constitute a finding by NHTSA that a safety-related defect does not exists on other model or model year vehicles outside of the recall scopes. The agency reserves the right to take further action if warranted by the circumstances.